1. Field of the Invention
This invention relates to an apparatus using a disc-shaped record bearing medium, such as disc player.
2. Description of the Prior Art
In the recording and/or reproducing apparatus using a rotation type record bearing medium of disc shape, for example, rotation type flexible magnetic disc, rotation of the magnetic disc is performed after an engaging hole of the center core in the central portion of the magnetic disc has been engaged with a spindle which is driven to rotate by an electric motor. This type of apparatus has a problem that when the engagement of the center core with the spindle is loose, it becomes impossible to make sure the magnetic disc does normal rotative motion during recording or reproduction, and conversely when the aforesaid engagement is tightened, the magnetic disc becomes difficult to load on the spindle.
Therefore, as will be more fully described later in FIG. 2, a method has been proposed that a magnetizable member is applied to the center core, while a magnet piece is mounted on the flanged portion of the spindle. However, even in such magnetic coupling method, it is difficult to assure that when the center core is put on the spindle, it takes a certain position relative to a reference surface, for example, the flange surface of the spindle. Therefore, it is difficult to hold the magnetic disc in a predetermined setting surface for maintenance of a predetermined aligning state between it and a recording and/or reproducing head. Also in a still picture recording and/or reproducing apparatus having the rigorous requirement for accuracy of alignment, the force necessary to load the center core on the spindle amounts up to hundreds of grams. As the magnet piece is of large size, therefore, the size and weight of the apparatus is hindered from being reduced.
On the other hand, there has been proposed an apparatus provided with a mechanism for pressing a portion of the magnetic disc against the spindle as in the floppy disc device. Since, in this type of apparatus, that portion of the apparatus which drives rotation of the disc operates under the condition that the aforesaid mechanism applies a pressure on the spindle through the disc, its load becomes large, causing the speed of rotation to vary at random.